Ceki, Thanks for your reply. In your email you wrote: - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - "The second form would work just fine as long as "thisPropertyName" has a setter." - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - I realize each property could be configured by name, but the underlying library is deep and complex. It currently has 49 optional properties. It would require a significant amount of work to add the required setters to the Custom Appender. It would require even more work to maintain the Appender as the underlying library evolves and changes. By providing a "pass-through' Properties configuration, the custom appender will have a long life on Github with less maintenance required. Instead of using the appender documentation, developers can simply refer to the configuration guide provided by the underlying library. The Appender will simply pass the configured properties through to the underlying library. Cheers, John Page